Image sensing apparatus

ABSTRACT

An image sensing apparats comprises a plurality of image sensing devices, a beam splitter for supplying an image of an object to the plurality of image sensing devices, and a plurality of shutters, each of which is disposed between the beam splitter and a respective one of the plurality of image sensing devices. The shutters are arranged to travel in the same direction relative to the image of an object formed on each of the plurality of image sensing devices and a detector is provided for detecting that all of the plurality of shutters means are in a full open state.

This is a continuation application under 37 CFR 1.62 of priorapplication U.S. patent application Ser. No. 947,941, filed Sep. 21,1992 now abandoned, which is a continuation of U.S. patent applicationSer. No. 658,091 filed Feb. 20, 1991, now abandoned, which is acontinuation of U.S. patent application Ser. No. 336,707 filed Apr. 12,1989, now U.S. Pat. No. 5,023,723.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an image sensing apparatus having a pluralityof image sensing devices.

2. Description of the Related Art

In order to enhance the resolution of an image produced by an imagesensing apparatus, particularly an electronic camera such as a stillvideo camera or the like, it is essential to increase the number ofpicture elements of the image sensing device of the apparatus. However,the increasable number of picture elements is limited in a case wherethe apparatus is the so-called single-plate or single-tube type camerausing a single image sensing device which is a solid-state image sensorsuch as a CCD (charge-coupled device) or a camera tube. In view of thislimit, it is conceivable to enhance the resolution by using a camerawhich has a plurality of image sensors and is called a multi-plate ormulti-tube type camera.

Meanwhile, there has recently appeared a still video camera of the kindhaving a mechanical shutter arranged for taking a picture of a movingobject.

However, the shutter of the camera of this kind has been arranged withinan optical path obtained before a photographing light flux is split foreach of the image sensing devices. The conventional arrangement thusallows the camera to use a single shutter. However, an optical pathbetween the shutter and each of the image sensors becomes long becauseof the arrangement. The long optical path makes use of a slit shutterdifficult. Therefore, the shutter cannot be set at a high speed. Theshutter thus tends to give the so-called shutter blur for a quick movingobject. Besides, it might cause some color deviation in the image outputof the camera.

SUMMARY OF THE INVENTION

The present invention is directed to the solution of the above-statedproblems of the prior art. It is therefore an object of the invention toprovide an image sensing apparatus of the above-stated kind which iscapable of operating at a high shutter speed without causing shutterblurring even for a quick moving object and produces an image having nocolor deviation.

It is another object of the invention to provide a shutter controlmechanism ensuring no color deviation of an image due to a discrepancyin exposure timing between the shutters of a plurality of image sensingdevices.

It is a further object of the invention to provide an image sensingapparatus wherein a flashing operation is arranged to be performed whenall the focal plane shutters of the apparatus are opened even in caseswhere the shutters do not uniformly open and close.

To attain the above-stated object, an embodiment of this invention isarranged as follows: Shutters are disposed in front of a plurality ofimage sensing devices in their incident optical paths; and the shutterelements of these shutters are arranged to travel in the same directionrelative to object's images to be formed on these image sensing devices.

With the shutters of the embodiment arranged in this manner, each of theimage sensing devices can be arranged to have a short optical pathlength. Therefore, each of the shutters can be set at a high shutterspeed. Further, since the shutters are arranged to travel in the samedirection relative to the object's image, the lengths of exposure timefor the picture elements of the image sensors (or image sensing devices)become substantially unvarying, so that the color deviation, etc.mentioned in the foregoing can be prevented.

Further, another embodiment of the invention is provided with exposuretiming adjustment means for causing shutters which are disposed in frontof a plurality of image sensing devices in their optical paths to beexposed at the same timing.

The above-stated arrangement enables the embodiment to prevent the colordeviation, etc. of the image due to the exposure timing deviation of thepicture elements of the image sensing devices even in taking a pictureof a quick moving object.

To attain the above-stated object, an image sensing apparatus arrangedaccording to this invention as an embodiment thereof comprises: aplurality of image sensors arranged to receive optical images of one andthe same object to be photographed; a plurality of focal plane shuttersdisposed respectively in front of the plurality of image sensors, eachof the plurality of focal plane shutters having leading and trailingblades; a plurality of leading blade travel completion detecting meansand a plurality of trailing blade travel start detecting means both ofwhich are disposed at the plurality of focal plane shuttersrespectively; and flashing control means for generating a flashing startsignal on the basis of a logical product signal obtained from outputs ofthe plurality of leading blade travel completion detecting means and forgenerating a flashing stop signal on the basis of a logical sum signalobtained from outputs of the plurality of trailing blade travel startdetecting means.

With the embodiment arranged in this manner, the flashing start signalis obtained after completion of the travel of all the leading blades ofthe plurality of focal plane shutters. The flashing stop signal isobtained when even one of the trailing blades of the focal planeshutters begins to travel. This enables the embodiment to have a flashunit which emits flash when all the shutters are open.

Other objects and features of the invention will become apparent fromthe following detailed description of embodiments thereof taken inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows by way of example the arrangement of the optical system ofa two-plate type camera which is arranged as a first embodiment of theinvention.

FIG. 2 schematically shows by way of example the shutter arrangement ofthe first embodiment.

FIG. 3 is a block diagram showing a shutter control circuit of the firstembodiment.

FIG. 4 shows by way of example the arrangement of the optical system ofa two-plate type camera which is arranged as a second embodiment of theinvention.

FIG. 5 shows the shutter mechanism of the second embodiment.

FIG. 6 is a block diagram showing a shutter control circuit of thesecond embodiment.

FIG. 7 shows the concept of third and fourth embodiments of theinvention.

FIG. 8 shows the arrangement of the essential parts of the thirdembodiment.

FIG. 9 is a circuit diagram showing the circuit arrangement of the thirdembodiment.

FIG. 10 is a circuit diagram showing the circuit arrangement of thefourth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the optical system arrangement of a two-plate type camerawhich is arranged according to this invention as a first embodimentthereof. The illustration includes a photo-taking lens TL; and atotal-reflection quick-return mirror 1. When a release switch which isnot shown is operated, an optical path changeover action is performed byraising the quick-return mirror 1 clockwise around a fulcrum 1a from itsposition on the side of a viewfinder optical system to its position onthe side of a photographing optical system. Prisms 2 and 3 jointly forma beam splitter which is arranged to split a photographing light flux.Reference numerals 4 and 5 denote first and second shutters. Numerals 6and 7 denote first and second solid-state image sensors which are CCDsor the like and are arranged as two image sensing devices. One of orboth of these image sensors may be camera tubes instead of solid-stateimage sensors. The shutters 4 and 5 are disposed in front of the lightflux incident on the CCDs 6 and 7 and in rear of the prisms 2 and 3,respectively.

The illustration further includes a prism 8; a focusing screen 9; apentagonal roof type prism 10; and an eyepiece lens 11. The incidentlight which comes through the photo-taking lens TL is selectivelydirected either to the viewfinder optical system or to the photographingoptical system through the turning movement of the quick-return mirror 1around the fulcrum la thereof. The viewfinder optical system is arrangedto convert an image formed on the focusing screen 9 into a non-reverseerecting image by means of the pentagonal roof type prism 10 and toenlarge it by means of the eyepiece lens 11 for sighting.

The photographing optical system is arranged to split the incident lightflux by means of the beam splitter which consists of the prisms 2 and 3and to guide the split light fluxes to the first and second CCDs 6 and7. The first and second shutters 4 and 5 which are, for example, focalplane shutters or the like are disposed just before the CCDs 6 and 7,respectively. In the case of this specific embodiment, the first CCD 6is arranged to obtain a luminance signal and the second CCD 7 to obtaina color signal. This arrangement, however, may be changed, for example,to use the first CCD 6 for detecting a green color and the second CCD 7for detecting red and blue colors.

FIG. 2 schematically shows by way of example the arrangement of each ofthe shutters. A known mechanism is shown in FIG. 2. Referring to FIG. 2,a base plate 21 is provided with an aperture 21a. An arm 22 has one endthereof rotatably attached to the base plate 21 by a pin 23. Another pin24 rotatably attaches the other end of the arm 22 to a leading blade 28which serves as a shutter element. Another arm 25 has its one endrotatably attached to the base plate 21 by a pin 26 and the other end tothe leading blade 28 by a pin 27. These arms 22 and 25 and pins 23, 24,26 and 27 form a parallelogrammic linkage. A trailing blade 35 whichserves as another shutter element is arranged to form anotherparallelogramic linkage in conjunction with arms 29 and 32 and pins 30,31, 33 and 34 in a manner similar to the leading blade 28.

A return spring 36 has its one end attached to the arm 22 and the otherend to the base plate 21. Another return spring 37 has its one endattached to the arm 32 and the other end to the base plate 21. A plunger38 is connected to the arm 22 in such a manner that, when energized, itcauses the arm 22 to turn clockwise around the pin 23. A plunger 39which is similar to the plunger 38 is connected to the arm 32 and isarranged to cause the arm 32 to turn clockwise around the pin 33 when itis energized.

The shutters which are respectively arranged in the above-stated mannerare disposed in front of the first and second CCDs 6 and 7 in theirincident light flux paths. In FIG. 1, these shutters are indicated byreference numerals 4 and 5. The traveling direction of the leading andtrailing blades 28 and 35 are respectively indicated by arrows A. Theoptical images incident on the CCDs 6 and 7 are formed in the samedirection. Therefore, the shutters 4 and 5 travel in the same directionrelative to the images.

FIG. 3 shows in a block diagram the arrangement of a circuit providedfor driving each of these shutters. Referring to FIG. 3, theillustration includes a system controller 41; a shutter driving circuit42; and a shutter release switch 43.

Each of the shutters operates as follows: When the shutter releaseswitch 43 is closed in response to a shutter release operation, theplungers 38 and 39 are energized by the system controller 41 and theshutter driving circuit 42 at a predetermined time intervalcorresponding to a shutter speed selected. When the plunger 38 is firstenergized, the arm 22 turns clockwise as viewed on FIG. 2 against theforce of the spring 36. This causes the leading blade 28 to movedownward (in the direction of arrow A) virtually in parallel. Theaperture 21a is uncovered to initiate an exposure. When the otherplunger 39 is energized next, the trailing blade 35 likewise movesdownward (in the direction of arrow A) virtually in parallel. Thiscovers the aperture 21a to terminate the exposure. After the end of theexposure, the current supply to each of the plungers 38 and 39 is cutoff. The leading and trailing blades 28 and 35 are then brought back totheir initial positions by the return springs 36 and 37.

As mentioned in the foregoing, the picture elements of each of the CCDs6 and 7 are not simultaneously exposed. They are exposed at differentpoints of time defined by the shutter blades 28 and 35. This presents noproblem if the camera has only a single image sensor. However, in thecase of a camera using a plurality of image sensors like thisembodiment, the corresponding picture elements of the different imagesensors must be exposed at the same point of time. If not, differentimages would be formed on the corresponding picture elements to bringabout a problem such as color deviation or discrepancy or the like.

To avoid the above-stated inconvenience, the embodiment of thisinvention is arranged to cause the leading and trailing blades 28 and 35of the first and second shutters 4 and 5 to travel in the same directionrelative to the object's images formed on the CCDs 6 and 7 (in thedirection of arrows A of FIGS. 1 and 2). In other words, the arrangementto have the shutters disposed in front of the plurality of image sensorsin the paths of their incident light fluxes enables the embodiment totake the picture of even a quickly moving object without any shutterblur. Further, the arrangement to cause the shutter elements (or blades)of both the shutters to travel in the same direction relative to theobject's image formed on the image sensors enables the embodiment togive an image of a high degree of quality having no color deviation.

It is well known that the focal plane shutter is arranged to make a slittravel exposure when the shutter speed is within the range of highshutter speeds. Therefore, with the shutters disposed in front of thetwo image sensors like in the case of this embodiment, a discrepancy inthe slit travel timing between the shutters brings about some differencebetween the images formed on the two image sensors according to themoving speed of the object, particularly in the event of a quicklymoving object. Then, this difference causes the color deviation or thelike of the image output of the camera and thus results in a loweredimage quality. A second embodiment of this invention is arranged tosolve this problem as described below:

FIG. 4 shows the optical system arrangement of a two-plate type cameraarranged according to this invention as the second embodiment. In FIG.4, the same component parts as those of FIGS. 1 and 2 are indicated bythe same reference numerals. Reference numerals 52, 54 and 55 denotelenses for the viewfinder optical system. Of these lenses, the lens 55serves as an eyepiece lens. The illustration further includes atotal-reflection mirror 53; a focusing screen 56; and low-pass filters59 and 59'.

FIG. 5 shows by way of example the arrangement of the first shutter 4 ofthe second embodiment in outline. The first and second shutters 4 and 5have their mechanisms arranged in the same manner. Referring to FIG. 5,the shutter includes a leading blade 61 and a trailing blade 66. Theleading blade 61 is provided with a leading blade spring 62, a leadingblade arresting hook 63, a leading blade magnet 64 and a leading blademagnet spring 65. The trailing blade 66 is arranged in a manner similarto the leading blade 61 and is provided with a trailing blade spring 67,a trailing blade arresting hook 68, a trailing blade magnet 69 and atrailing blade magnet spring 70.

In FIG. 5, the shutter is shown as in a state in which the leading andtrailing blades 61 and 66 are charged (set in their charged positions)by a shutter charge mechanism which is not shown. The leading blade 61covers an optical path 71 of the first CCD (image sensor) 6 whichcorresponds to an aperture. When a power supply to the leading magnet 64is released in response to a shutter release operation, the leadingmagnet spring 65 causes the leading blade arresting hook 63 to turnclockwise to unlock the leading blade 61. The leading blade 61 is thenturned counterclockwise by the leading blade spring 62 to begin toexpose the first CCD 6 by unblocking the optical path 71.

After the lapse of a period of time corresponding to a set shutterspeed, a power supply to the trailing blade magnet 69 is released. Thetrailing blade arresting hook 68 is caused to turn clockwise by thetrailing blade magnet spring 70 to unlock the trailing blade 66. Thetrailing blade spring 67 then causes the trailing blade 66 to turncounterclockwise to block the optical path 71 and to terminate theexposure action on the first CCD 6.

In a case where the shutter is arranged to perform a slit travelingaction at a high speed, the picture of a moving object cannot beadequately taken if there arises a discrepancy in exposure timingbetween the first and second shutters 4 and 5 as mentioned in theforegoing. In other words, the discrepancy in exposure timing bringsabout discrepancy in position between an image formed on the first CCD 6and an image formed on the second CCD 7. This results in an image colordeviation which affects the image output of the camera. To solve thisproblem, the shutter control circuit 74 of the second embodiment isprovided with an adjustment timer 79 which is arranged to serve assynchronizing means for eliminating any discrepancy in exposure timingbetween the first and second shutters 4 and 5, as shown in FIG. 6.

FIG. 6 shows the circuit arrangement of the second embodiment includingthe above-stated shutter control circuit 74. When a release switch 75 isturned on, a shutter start signal control circuit 76 supplies shutterstart signals to a first shutter timer 77 and a second shutter timer 78after the lapse of a given period of time determined by taking intoconsideration a length of time required for aperture adjustment and araising (springing-up) action on the quick-return mirror 1. Then, insynchronism with this shutter start signal, the first and second shuttertimers 77 and 78 produce signals for turning on the magnets 64respectively. Then, after the lapse of a length of time set by a shuttertime setting circuit 88, the timers 77 and 78 produce signals forturning on the magnets 69 respectively. The shutter start signal to besupplied from the shutter start signal control circuit 76 to the secondshutter timer 78 is supplied to the latter via an adjustment timer 79which is provided for the purpose of synchronizing the exposure timingof the second shutter timer 78 with that of the first shutter timer 77.

The first and second shutter timers 77 and 78 are arranged to actuatethe leading blade magnets 64 shown in FIG. 5 via applicable magnetdrivers 80 and 81, respectively. The magnet actuating points of time ofthe two shutters 4 and 5 can be synchronized (equalized) with each otherby adjusting the starting points of time of the first and second shuttertimers 77 and 78 by means of the above-stated adjustment timer 79.

It may appear, from FIG. 6, that the start of the second shutter 5 isdelayed and takes place later than that of the first shutter 4 by alength of time required for the operation of the adjustment timer 79.However, in actuality, the shutter start signal control circuit 76 isarranged to have the signal for the second shutter 5 produced earlierthan the signal for the first shutter 4 and supplied to the adjustmenttimer 79. Such being the arrangement, the start timing adjustmentbetween the two shutters 4 and 5 can be carried out both in positive andnegative directions. Further, as regards the synchronizing means to beused for this purpose, any circuit element that has a delaying functioncan be employed as the synchronizing means.

In the case of the embodiment described, this invention is applied to astill video camera having two image sensors. The principle of theinvention is, however, of course applicable to any camera of the kindhaving more than two image sensors. For example, the invention isapplicable also to such a camera that is arranged to have three imagesensors for obtaining image signals of three colors R (red), G (green)and B (blue) and to separate colors by means of dichroic mirrors.

Further, while the invention is applied to the multi-plate type camerawherein a plurality of solid-state image sensors such as CCDs or thelike are used as the image sensing devices, the advantageous effect ofthe invention is of course likewise attainable by applying it to acamera of the multi-tube type wherein camera tubes are employed as theimage sensing devices.

With a plurality of shutters arranged respectively in combination with aplurality of image sensing devices to be started independently of eachother, the second embodiment is arranged to cause the exposure effectingpoints of time of these shutters to coincide with each other asdescribed in the foregoing. The arrangement enables the secondembodiment to enhance the quality of image output thereof by preventingany color deviation or the like from occurring in shooting a movingobject.

In carrying out a flash photographing operation with a camera of thekind having a focal plane shutter, a flash unit must be allowed to emitflash when the shutter is fully opened. In the case of a multi-platetype still video camera like the embodiment described, the flash unitmust be arranged to emit flash when all the shutters are open. However,a plurality of focal plane shutters cannot be opened and closed inexactly the same manner. The fully opening point of time of one shuttertends to differ from that of another shutter. Third and fourthembodiments of this invention which are shown in FIGS. 7 to 9 arearranged to be capable of solving this problem.

FIG. 7 shows the concept of the third embodiment. FIG. 8 shows themechanism of the essential parts of a two-plate type still video camerawhich is arranged as the third embodiment of the invention. FIG. 9 is acircuit diagram of the third embodiment. In these drawings, the sameparts as those of FIGS. 1 to 6 are indicated by the same referencenumerals.

Referring to FIG. 7, a reference numeral 101 denotes a flash unit, and anumeral 102 a still video camera. The flash unit 101 is arranged tobegin to emit flash in response to a flashing start signal output fromthe camera 102 and to stop flashing in response to a flashing stopsignal output from the camera. While the flash unit 101 is illustratedas arranged discretely from the camera, it can be arranged in the samemanner in a case where the camera incorporates it therein.

FIG. 8 shows the arrangement of each of a pair of focal plane shutterstogether with a corresponding image sensor part. The third embodimentdiffers from the second embodiment shown in FIG. 5 in the followingpoint: The third embodiment is provided with a leading blade travelcompletion detection switch 83a and a trailing blade travel startdetection switch 84a. Further, the magnets 64 and 69 are arranged tonormally stay away from hooks 63 and 68 respectively.. The springs 65and 70 are arranged to urge these hooks in the direction opposite to theurging direction of the arrangement shown in FIG. 5. Further, in FIG. 8,the shutter is shown as in a state of being charged by a chargingmechanism which is not shown.

When a current is supplied to the leading blade magnet 64, the magnet 64attracts the hook 63 to unlock the leading blade 61. This allows theleading blade 61 to turn counterclockwise by a spring 62. An aperture 71is uncovered by this. Immediately after the leading blade 61 has movedcompletely to the outside of the aperture 71, the leading blade 61 comesin touch with the leading blade travel completion detection switch 83ato turn the latter off.

Next, when a current is supplied to the trailing blade magnet 69 afterthe lapse of a given period of time, the magnet 69 attracts the hook 68to unlock the latter. A spring 67 then causes the trailing blade 66 tocover the aperture 71 by turning counterclockwise. Immediately beforethe trailing blade 66 enters the aperture 71, the trailing blade 66comes in touch with the trailing blade travel start detection switch 84ato turn it off.

The third embodiment is provided with two focal plane shutters which arerespectively combined with two image sensors in two pairs and arearranged in the manner as described above.

FIG. 9 shows the third embodiment in a circuit diagram. A leading bladetravel completion detection switch 83a is arranged to detect completionof the travel of the leading blade of a first focal plane shutter (or afirst shutter) 83. A trailing blade travel start detection switch 84a isarranged to detect commencement of the travel of the trailing shutterblade of the first shutter. A leading blade travel completion detectionswitch 83b is arranged to detect completion of the travel of the leadingblade of a second (focal plane) shutter. A trailing blade travel startdetection switch 84b is arranged to detect commencement of the travel ofthe trailing blade of the second shutter. These switches 83a, 83b, 84aand 84b are arranged such that, when they are opened, the input levelsof an AND gate 85 and an OR gate 86 which are connected to theseswitches change from low levels to high levels respectively.

Therefore, when the switches 83a and 83b open upon completion of thetravel of both the leading blades of the first and second shutters, theoutput level of the AND gate 85 becomes high to give a flashing startsignal. When one of the two switches 84a and 84b opens upon commencementof the travel of the trailing blade of one of the first and secondshutters, the output level of the OR gate 86 becomes high to give aflashing stop signal. A reference numeral 87 denotes a power source.

The above-stated arrangement enables the third embodiment to cause theflash unit 101 to emit flash with the apertures of both the first andsecond shutters fully opened irrespectively of any discrepancy inopening and closing actions between the two shutters.

FIG. 10 is a circuit diagram showing a fourth embodiment of thisinvention. The mechanical arrangement of the fourth embodiment includestwo pairs or combinations of focal plane shutters and image sensorsexcluding the mechanical switches of FIG. 8. Referring to FIG. 10, asuction type magnet 64a is arranged to unlock the leading blade of thefocal plane shutter of the first shutter-and-image sensor pair, i.e. afirst shutter. A suction type magnet 69a is arranged to unlock thetrailing blade of the first shutter. A magnet 64b is arranged to unlockthe leading blade of the focal plane shutter of the secondshutter-and-image sensor pair, i.e. a second shutter. A magnet 69b isarranged to unlock the trailing blade of the second shutter.

The magnets 64a, 69a, 64b and 69b are arranged to be driven by a shuttercontrol circuit 125. The input side of the magnet 64a is connected toone of the input terminals of an AND gate 130 via a timer 126. The inputside of the magnet 64b is connected to the other input terminal of theAND gate 130 via a timer 127. The input side of the magnet 69a isconnected to one of the input terminals of an OR gate 131 via a timer128. The input side of the magnet 69b is connected to the other inputterminal of the OR gate 131 via a timer 129.

With the circuit arranged in the above-stated manner, when a releaseswitch 75 is started after the shutter time is set at a full open timevalue by a shutter time setting circuit 88, the shutter control circuit125 supplies currents to the leading blade magnets 64a and 64b of thefirst and second shutters after completion of the operation of a mirrorand that of an iris which are not shown. Then the timers 126 and 127,which are arranged to measure a length of time corresponding to a periodof time between commencement of a power supply to the leading blademagnets and the end of the travels of the leading blades, begin tooperate. Upon completion of the time measurement by these timers, thelevels of both the inputs of the AND gate 130 become high. The outputlevel of the AND gate 130 then becomes high to give the flashing startsignal.

When a power supply is effected from the shutter control circuit 125 tothe trailing blade magnets 69a and 69b, it actuates the timers 128 and129 which are arranged to measure a length of time corresponding to aperiod of time between commencement of the power supply to the trailingblade magnet and entry of the trailing blade in the aperture.

Upon completion of the time measurement by any one of the timers 128 and129, the level of one of the inputs of the OR gate 131 becomes high togive the flashing stop signal. To absorb any manufacturing unevennessexisting between the first and second shutters, the above-stated fourtimers 126 to 129 are arranged to have their measuring time adjustable.

The above described arrangement enables the fourth embodiment to ensurethat the flash unit emits flash only when the apertures of both thefirst and second shutters are fully opened irrespectively of anyoperation discrepancy between the two shutters.

While the invention is applied to the two-plate type still video camerasin the case of the embodiments described in the foregoing, the inventionis likewise applicable to still video cameras of the type using three ormore image sensors.

In the case of a still video camera having two or more focal planeshutters paired with image sensors, the arrangement of the third orfourth embodiment described enables the camera to cause a flash unit toemit flash accurately at a point of time when all the shutters areopened irrespectively of discrepancy in the operation timing among theshutters.

What is claimed is:
 1. An image sensing apparatus, comprising:(a) aplurality of image sensing devices; (b) a beam splitter for supplying animage of an object to said plurality of image sensing devices; (c) aplurality of shutter means, each of which is disposed between said beamsplitter and a respective one of said plurality of image sensingdevices, said shutter means being arranged to travel in the samedirection relative to the image of an object formed on each of saidplurality of the image sensing devices; (d) detection means fordetecting that all of said plurality of shutter means are in a full openstate; and (e) at least one filter means for passing a predeterminedcolor of said image to a corresponding one of said plurality of imagesensing devices.
 2. An apparatus according to claim 1, wherein said beamsplitter includes a prism.
 3. An apparatus according to claim 1, whereinsaid plurality of image sensing devices comprises a first device forforming a luminance signal and a second device for forming a colorsignal.
 4. An apparatus according to claim 1, further comprisingsynchronizing means for causing said plurality of shutter means whichare respectively disposed in front of said plurality of image sensingdevices to perform opening and closing actions in synchronism with eachother.
 5. An apparatus according to claim 4, wherein said synchronizingmeans includes delaying means.
 6. An apparatus according to claim 5,wherein said delaying means includes a timer.
 7. An apparatus accordingto claim 1, further comprising flash means for emitting flash when saiddetection means has detected that all of said plurality of shutter meansare in the full open state.
 8. An apparatus according to claim 7,further comprising flash means for emitting flash when said detectingmeans has detected that all of said shutter means are in a full openstate.
 9. An apparatus according to claim 8, further comprising stoppingmeans for stopping said flash means from emitting flash when saiddetection means has detected that one of said plurality of shutter meansis no longer in a full open state.
 10. An optical apparatus,comprising:(a) first optical means for conducting an optical image beamof an object into a plurality of optical paths; (b) a plurality ofsecond optical means disposed on said plurality of optical paths,respectively, to turn said optical paths ON and OFF, said second opticalmeans being arranged to travel in the same direction relative to theoptical image conducted through each of said plurality of optical paths;(c) a plurality of image sensors for photo-electrically converting theimage beams conducted through the plurality of optical paths,respectively; (d) detection means for detecting that all of saidplurality of second optical means are in a full open state; and (e) atleast one filter means for passing a predetermined color of said imageto a corresponding one of said plurality of image sensors.
 11. Anapparatus according to claim 10, wherein said first optical meansincludes a beam splitter.
 12. An apparatus according to claim 11,wherein the beam splitter includes a prism.
 13. An apparatus accordingto claim 11, further comprising stopping means for stopping said flashmeans from emitting flash when said detecting means has detected thatone of said plurality of second optical means is no longer in a fullopen state.
 14. An apparatus according to claim 10, wherein said secondoptical means includes shutter means.
 15. An apparatus according toclaim 10, wherein the image beams conducted to said plurality of opticalpaths include the same object image.
 16. An apparatus according to claim10, further comprising synchronizing means for synchronizing exposuretimings of said plurality of second optical means.
 17. An apparatusaccording to claim 10, further comprising flash means for emitting flashwhen said detecting means has detected that all of said plurality ofsecond optical means are in a full open state.
 18. An apparatusaccording to claim 10, wherein said plurality of image sensing devicescomprises a first device for forming a luminance signal and a seconddevice for forming a color signal.